Research and analysis

Vehicle Market Surveillance Unit: results of the 2021 emissions programme

Published 18 May 2023

Applies to England, Scotland and Wales

Introduction

The Driver and Vehicle Standards Agency (DVSA) has a market surveillance unit, which inspects vehicles, trailers and equipment to make sure they meet safety and environmental standards.

This report sets out the findings of vehicle and component testing during 2021. You can also download the unprocessed raw data for all of the tests carried out.

There’s an annex that explains some of the emissions reduction technologies mentioned in the report.

How DVSA selected the sample of vehicles tested

DVSA aims to check a representative selection of the most popular vehicle types used on UK roads. In 2021, we carried out tests on:

  • diesel cars
  • petrol cars
  • light duty vans
  • heavy goods vehicles (HGVs)

The vehicles were chosen based on their UK sales, with other vehicles added in to make sure a wide range of manufacturers were included.

DVSA sourced vehicles from hire fleets or bus operators.

The vehicles were not provided by manufacturers and they could not prepare or modify the vehicles before they were tested.

What tests were carried out

DVSA tested the vehicles to make sure they conformed to European emission standards:

  • Euro 6 for light duty vehicles
  • Euro VI for heavy duty vehicles

The types of tests DVSA carried out depended on:

  • the type of vehicle
  • whether the vehicle was New European Drive Cycle (NEDC) approved or Worldwide Harmonised Light Vehicle Test Procedure (WLTP) approved

Cars and light vans

For cars and light vans, DVSA carried out the following tests:

  • cold test in a laboratory
  • hot test in a laboratory
  • on-road test - called Real Driving Emissions (RDE)
  • track test

Before carrying out the tests the vehicles:

  • were checked for any defects that could affect the emissions control system
  • had their fuel drained and replaced with standard laboratory reference fuel

The majority of cars and light vans tested in 2021 were type-approved using the Worldwide Harmonised Light Vehicle Test Procedure (WLTP) and Real Driving Emissions (RDE) test. DVSA tested vehicles using these regulations.

Vehicles approved under NEDC do not need to meet the requirements of the WLTP or RDE tests.

DVSA still carried out on-road tests and track tests on NEDC approved vehicles in order to understand how they perform under real world conditions.

Cold tests in a laboratory

The vehicle is given a standard pre-conditioning test relevant to its approval. It’s then left in a temperature-controlled room so that the whole vehicle including engine oil and coolant is ‘soaked’ to a temperature between 20°C and 30°C (as specified in type approval regulations). Following that the test starts with emissions measured from engine start.

This is a legislative test with limits that a vehicle’s emissions must not exceed.

Hot tests in a laboratory

This test is the same test as the cold test, but starts with a fully warmed up engine.

This is not a legislative test and is carried out to gather additional information on the vehicle’s performance.

New European Driving Cycle (NEDC) tests

The test consists of 4 repeated urban driving cycles and one extra-urban driving cycle. These drive cycles cover 11 kilometres (km) and take 20 minutes to complete. The test has an average speed of 34km per hour with the maximum being 120km per hour.

Worldwide Harmonised Light Vehicle Test Procedure (WLTP) tests

WLTP replaced the NEDC test procedure for measuring the official fuel consumption, carbon dioxide (CO2) and pollutant emissions of new cars in September 2017. It became mandatory for all new cars powered by an internal combustion engine by September 2018.

WLTP tests are designed to give a more accurate indication of how much fuel the vehicle will use, and the pollutants emitted during driving.

The WLTP test takes 30 minutes to complete and covers just over 23km with an average speed of 45km per hour and maximum speed of 131km per hour.

On-road test - Real Driving Emissions (RDE)

This test is carried out on public roads using Portable Emissions Measuring System (PEMS) equipment. This test measures pollutants while the vehicle is being driven.

This test involves driving the vehicle for around 1 and a half to 2 hours over a test route on public roads. The route included urban, rural and motorway driving and tests were carried out during the day in normal traffic conditions.

If temperatures drop below 3°C during this test, this is considered ‘extended’ conditions and the emissions results for the test are divided by a factor of 1.6. For transparency reasons in this report ‘raw’ RDE results have not been post-processed and have not had additional factors such as the extended conditions factor applied.

For NEDC approved vehicles and some WLTP approved vehicles sold before September 2019, this is not a legislative test. For these vehicles, it is an additional test that DVSA carried out to understand how they perform under real world conditions.

Track tests

This test is carried out on a closed track using Portable Emissions Measuring System (PEMS) equipment. It’s designed to check that the vehicle’s emissions did not increase disproportionately compared to the laboratory tests.

The test follows the driving pattern used in WLTP tests. It is carried out by providing the driver with a screen showing a trace of the speed versus time that they needed to maintain for each section.

Heavy goods vehicles (HGVs)

For HGVs, DVSA carried out an on-road test using Portable Emissions Measuring System (PEMS) equipment.

Before carrying out the tests the vehicles:

  • were checked for any defects that could affect the emissions control system
  • had their fuel drained and replaced with standard reference fuel

This test involves driving the vehicle for around 2 and a half hours over a test route on public roads. The route included urban, rural and motorway driving and tests were carried out during the day in normal traffic conditions.

The emissions measured in this test are normalised to the laboratory engine test using carbon dioxide as an assessment of the amount of ‘work done’. We use this to calculate mass emissions per unit of energy (measured in kilowatt-hours, kWh).

The result is then compared to the laboratory limit to determine whether it is within the conformity factor specified in legislation.

The conformity factor is the maximum permitted ratio of the normalised test result in g/kWh compared to the emissions limit specified for type approval engine testing.

For HGVs, the nitrogen oxides (NOx), hydrocarbons (HC) and carbon monoxide (CO) levels all have a conformity factor of 1.5. This is because:

  • this test covers a much wider range of operating conditions than the dynamometer engine test
  • real world on-road emissions measurements are subject to greater margins of uncertainty

Where the tests were carried out

Tests were carried out at a selection of commercial emission test laboratories across the UK.

DVSA did not use laboratories that are owned by vehicle manufacturers.

Discussing the results with manufacturers

Where vehicles were found to have performed poorly, manufacturers were given the opportunity to explain the test results and describe the emission control strategies they used.

A summary of these discussions is included in the test conclusions in the results section. They provide insight into why a vehicle may achieve the legal emissions limit when tested on the official test cycle, but may emit significantly higher emissions in other situations.

Results: diesel cars

Raw data for diesel car tests

You can download the unprocessed raw data showing the results of each test that was conducted on these vehicles.

BMW 3 Series

Vehicle details


Make: BMW

Model: 3 Series 320d (2020MY)

Engine and fuel type: 1995cc 140kW Diesel

Transmission: Automatic

Emission standard: Euro 6d-temp

Test reference: 33025

Tested: March 2021

Tests conducted

The following tests were completed on this vehicle to assess the emission control systems and tailpipe emissions:

  • vehicle preparation inspection
  • laboratory pre-conditioning
  • WLTC cold test in the laboratory
  • WLTC hot test in the laboratory
  • RDE on-road test
  • WLTC test carried out on a test track

Conclusion from tests

The BMW 3 Series was compliant with all required tailpipe pollutant emission limits under the WLTC cold and RDE legislative tests.

A number of non-regulatory tests were also conducted to understand if the emissions behaviour of the vehicle changed significantly outside of the legislative test, which might be an indication of prohibited emission strategies.

From the results of both legislative and non-legislative testing, DVSA does not have reason to believe that the BMW 3 Series tested was non-compliant with its legal emissions performance requirements.

WLTC lab tests: BMW 3 Series

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM  (mg/km) PN (#/km)
Cold test 1 50.17 26.91 48.74 0.063 1.01E+09
Legislative limit 500 80 170 4.5 6.00E+11
Hot test 1 22.05 49.95 81.48 0.077 2.96E+08

RDE tests: BMW 3 Series

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM  (mg/km) PN (#/km)
COC figure (declared max RDE)   168     9.00E+11
Test 1 42.26 43.45     7.19E+08
Conformity factor limit   2.1     1.5
RDE legislative limit   168     9.00E+11

WLTC track tests: BMW 3 Series

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM  (mg/km) PN (#/km)
Test 1 105.4 39.1     1.19E+09
Test 2 113.6 44.87     1.05E+09

Go back to the list of diesel cars.

Jaguar F Pace

Vehicle details


Make: Jaguar

Model: F Pace (2020MY)

Engine and fuel type: 1999cc 177kW Diesel

Transmission: Automatic

Emission standard: Euro 6d-temp

Test reference: 33026

Tested: March 2021

Tests conducted

The following tests were completed on this vehicle to assess the emission control systems and tailpipe emissions:

  • vehicle preparation inspection
  • laboratory pre-conditioning
  • WLTC cold test in the laboratory
  • WLTC hot test in the laboratory
  • RDE on-road test
  • WLTC test carried out on a test track

Conclusion from tests

The Jaguar F Pace was compliant with all required tailpipe pollutant emission limits under the WLTC cold and RDE legislative tests.

A number of non-regulatory tests were also conducted to understand if the emissions behaviour of the vehicle changed significantly outside of the legislative test, which might be an indication of prohibited emission strategies.

From the results of both legislative and non-legislative testing, DVSA does not have reason to believe that the Jaguar F Pace Series tested was non-compliant with its legal emissions performance requirements.

WLTC lab tests: Jaguar F Pace

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM  (mg/km) PN (#/km)
Cold test 1 65.61 42.79 76.72 0.068 2.57E+10
Legislative limit 500 80 170 4.5 6.00E+11
Hot test 1 26.71 43.69 68.91 0.015 2.32E+10

RDE tests: Jaguar F Pace

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM  (mg/km) PN (#/km)
COC figure (declared max RDE)   168     6.00E+11
Test 1 55.32 24.91     2.83E+10
Conformity factor limit   2.1     1.5
RDE legislative limit   168     9.00E+11

WLTC track tests: Jaguar F Pace

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM  (mg/km) PN (#/km)
Test 1 154.3 41.9     5.97E+10
Test 2 216.9 56.71     5.45E+10

Go back to the list of diesel cars.

Mercedes-Benz A Class

Vehicle details


Make: Mercedes-Benz

Model: A Class (2020MY)

Engine and fuel type: 1461cc 85kW Diesel

Transmission: Automatic

Emission standard: Euro 6d-temp

Test reference: 33148

Tested: May 2021

Tests conducted

The following tests were completed on this vehicle to assess the emission control systems and tailpipe emissions:

  • vehicle preparation inspection
  • laboratory pre-conditioning
  • WLTC cold test in the laboratory
  • WLTC hot test in the laboratory
  • RDE on-road test
  • WLTC test carried out on a test track

Conclusion from tests

The Mercedes-Benz A Class was compliant with all required tailpipe pollutant emission limits under the WLTC cold and RDE legislative tests.

A number of non-regulatory tests were also conducted to understand if the emissions behaviour of the vehicle changed significantly outside of the legislative test, which might be an indication of prohibited emission strategies.

From the results of both legislative and non-legislative testing, DVSA does not have reason to believe that the Mercedes-Benz A Class tested was non-compliant with its legal emissions performance requirements.

WLTC lab tests: Mercedes-Benz A Class

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM  (mg/km) PN (#/km)
Cold test 1 24.78 31.88 37.63 0.156 7.04E+10
Legislative limit 500 80 170 4.5 6.00E+11
Hot test 1 0.016 19.16 21.71 0.09 6.99E+10

RDE tests: Mercedes-Benz A Class

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM  (mg/km) PN (#/km)
COC figure (declared max RDE)   168     9.00E+11
Test 1 36.87 25.48     7.02E+10
Conformity factor limit   2.1     1.5
RDE legislative limit   168     9.00E+11

WLTC track tests: Mercedes-Benz A Class

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM  (mg/km) PN (#/km)
Test 1 81.23 58.77     1.04E+11

Go back to the list of diesel cars.

Mercedes-Benz E Class

Vehicle details


Make: Mercedes-Benz

Model: E Class E220 D AMG (2019MY)

Engine and fuel type: 1950cc 143kW Diesel

Transmission: Automatic

Emission standard: Euro 6d-temp

Test reference: 33231

Tested: February 2021

Tests conducted

The following tests were completed on this vehicle to assess the emission control systems and tailpipe emissions:

  • vehicle preparation inspection
  • laboratory pre-conditioning
  • WLTC cold test in the laboratory
  • WLTC hot test in the laboratory
  • RDE on-road test
  • WLTC test carried out on a test track

Conclusion from tests

The Mercedes-Benz E Class was compliant with all required tailpipe pollutant emission limits under the WLTC cold and RDE legislative tests.

A number of non-regulatory tests were also conducted to understand if the emissions behaviour of the vehicle changed significantly outside of the legislative test, which might be an indication of prohibited emission strategies.

From the results of both legislative and non-legislative testing, DVSA does not have reason to believe that the Mercedes-Benz E Class tested was non-compliant with its legal emissions performance requirements.

WLTC lab tests: Mercedes-Benz E Class

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM  (mg/km) PN (#/km)
Cold test 1 9.482 19.75 24.4 0.226 1.03E+10
Legislative limit 500 80 170 4.5 6.00E+11
Hot test 1 1.042 18.73 21.1 0.04 2.81E+10

RDE tests: Mercedes-Benz E Class

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM  (mg/km) PN (#/km)
COC figure (declared max RDE)   168     6.00E+11
Test 1 33.07 7.74     1.03E+10
Conformity factor limit   2.1     1.5
RDE legislative limit   168     9.00E+11

WLTC track tests: Mercedes-Benz E Class

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM  (mg/km) PN (#/km)
Test 1 74.14 21.93     1.92E+08

Go back to the list of diesel cars.

Mercedes-Benz Vito Tourer

Vehicle details


Make: Mercedes-Benz

Model: Vito Tourer (2019MY)

Engine and fuel type: 2143cc Diesel

Transmission: Automatic

Emission standard: Euro 6c

Test reference: 33029

Tested: May 2021

Tests conducted

The following tests were completed on this vehicle to assess the emission control systems and tailpipe emissions:

  • vehicle preparation inspection
  • laboratory pre-conditioning
  • WLTC cold test in the laboratory
  • WLTC hot test in the laboratory
  • RDE on-road test
  • WLTC test carried out on a test track

Conclusion from tests

The Mercedes-Benz Vito was compliant with all required tailpipe pollutant emission limits under the WLTC cold and RDE legislative tests.

A number of non-regulatory tests were also conducted to understand if the emissions behaviour of the vehicle changed significantly outside of the legislative test, which might be an indication of prohibited emission strategies.

From the results of both legislative and non-legislative testing, DVSA does not have reason to believe that the Mercedes-Benz Vito tested was non-compliant with its legal emissions performance requirements.

WLTC lab tests: Mercedes-Benz Vito Tourer

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM  (mg/km) PN (#/km)
Cold test 1 44.14 68.58 75.7 0.095 6.68E+09
Legislative limit 500 80 170 4.5 6.00E+11
Hot test 1 0.54 61.66 64.99 0.268 1.21E+10

RDE tests: Mercedes-Benz Vito Tourer

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM  (mg/km) PN (#/km)
COC figure (declared max RDE)   168     6.00E+11
Test 1 0 41.0     5.03E+09
Conformity factor limit   2.1     1.5
RDE legislative limit   168     9.00E+11

WLTC track tests: Mercedes-Benz Vito Tourer

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM  (mg/km) PN (#/km)
Test 1 129.8 68.89     1.11E+10

Go back to the list of diesel cars.

Peugeot 3008

Vehicle details


Make: Peugeot

Model: 3008 (2020MY)

Engine and fuel type: 1499cc Diesel

Transmission: Automatic

Emission standard: Euro 6d-temp

Test reference: 33264

Tested: May 2021

Tests conducted

The following tests were completed on this vehicle to assess the emission control systems and tailpipe emissions:

  • vehicle preparation inspection
  • laboratory pre-conditioning
  • WLTC cold test in the laboratory
  • WLTC hot test in the laboratory
  • RDE on-road test
  • WLTC test carried out on a test track

Conclusion from tests

The Peugeot 3008 was compliant with all required tailpipe pollutant emission limits under the WLTC cold and RDE legislative tests.

A number of non-regulatory tests were also conducted to understand if the emissions behaviour of the vehicle changed significantly outside of the legislative test, which might be an indication of prohibited emission strategies.

From the results of both legislative and non-legislative testing, DVSA does not have reason to believe that the Peugeot 3008 tested was non-compliant with its legal emissions performance requirements.

WLTC lab tests: Peugeot 3008

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM  (mg/km) PN (#/km)
Cold test 1 74.72 52.36 58.09 0.037 2.53E+10
Legislative limit 500 80 170 4.5 6.00E+11
Hot test 1 5.639 40.74 42.26 0.044 3.25E+10

RDE tests: Peugeot 3008

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM  (mg/km) PN (#/km)
COC figure (declared max RDE)   80     6.00E+11
Test 1 9.083 27.9     4.15E+10
Conformity factor limit   1.43     1.5
RDE legislative limit   114.4     9.00E+11

WLTC track tests: Peugeot 3008

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM  (mg/km) PN (#/km)
Test 1 9.083 57.4     4.06E+10

Go back to the list of diesel cars.

Skoda Octavia

Vehicle details


Make: Skoda

Model: Octavia (2020MY)

Engine and fuel type: 1598cc 85kW Diesel

Transmission: Manual 5 speed

Emission standard: Euro 6d-temp

Test reference: 3

Tested: March 2021

Tests conducted

The following tests were completed on this vehicle to assess the emission control systems and tailpipe emissions:

  • vehicle preparation inspection
  • laboratory pre-conditioning
  • WLTC cold test in the laboratory
  • WLTC hot test in the laboratory
  • RDE on-road test
  • WLTC test carried out on a test track

Conclusion from tests

The Skoda Octavia was compliant with all required tailpipe pollutant emission limits under the WLTC cold and RDE legislative tests.

A number of non-regulatory tests were also conducted to understand if the emissions behaviour of the vehicle changed significantly outside of the legislative test, which might be an indication of prohibited emission strategies.

From the results of both legislative and non-legislative testing, DVSA does not have reason to believe that the Skoda Octavia tested was non-compliant with its legal emissions performance requirements.

WLTC lab tests: Skoda Octavia

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM  (mg/km) PN (#/km)
Cold test 1 11.7 22.62 26.27 0.049 2.32E+09
Legislative limit 500 80 170 4.5 6.00E+11
Hot test 1 0.012 24.85 26.43 0.045 2.04E+09

RDE tests: Skoda Octavia

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM  (mg/km) PN (#/km)
COC figure (declared max RDE)   168     6.00E+11
Test 1 0 9.88     9.87E+07
Conformity factor limit   2.1     1.5
RDE legislative limit   168     9.00E+11

WLTC track tests: Skoda Octavia

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM  (mg/km) PN (#/km)
Test 1 24.49 26.48     1.56E+08

Go back to the list of diesel cars.

Vauxhall Insignia

Vehicle details


Make: Vauxhall

Model: Insignia (2019MY)

Engine and fuel type: 1956cc 125kW Diesel

Transmission: Manual 6 speed

Emission standard: Euro 6d-temp

Test reference: 33281

Tested: April 2021

Tests conducted

The following tests were completed on this vehicle to assess the emission control systems and tailpipe emissions:

  • vehicle preparation inspection
  • laboratory pre-conditioning
  • WLTC cold test in the laboratory
  • WLTC hot test in the laboratory
  • RDE on-road test
  • WLTC test carried out on a test track

Conclusion from tests

The Vauxhall Insignia was compliant with all required tailpipe pollutant emission limits under the WLTC cold and RDE legislative tests.

A number of non-regulatory tests were also conducted to understand if the emissions behaviour of the vehicle changed significantly outside of the legislative test, which might be an indication of prohibited emission strategies.

From the results of both legislative and non-legislative testing, DVSA does not have reason to believe that the Vauxhall Insignia tested was non-compliant with its legal emissions performance requirements.

WLTC lab tests: Vauxhall Insignia

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM  (mg/km) PN (#/km)
Cold test 1 49.58 46.64 65.75 0.149 2.14E+09
Legislative limit 500 80 170 4.5 6.00E+11
Hot test 1 18.87 46.25 58.5 0.144 9.10E+08

RDE tests: Vauxhall Insignia

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM  (mg/km) PN (#/km)
COC figure (declared max RDE)   168     6.00E+11
Test 1 3.03 29.27     5.02E+08
Conformity factor limit   2.1     1.5
RDE legislative limit   168     9.00E+11

WLTC track tests: Vauxhall Insignia

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM  (mg/km) PN (#/km)
Test 1 31.93 39.98     5.50E+08

Go back to the list of diesel cars.

Volvo V90

Vehicle details


Make: Volvo

Model: V90 (2020MY)

Engine and fuel type: 1969cc HEV Diesel

Transmission: Automatic

Emission standard: Euro 6d

Test reference: 33150

Tested: June 2021

Tests conducted

The following tests were completed on this vehicle to assess the emission control systems and tailpipe emissions:

  • vehicle preparation inspection
  • laboratory pre-conditioning
  • WLTC cold test in the laboratory
  • WLTC hot test in the laboratory
  • RDE on-road test
  • WLTC test carried out on a test track

Conclusion from tests

The Volvo V90 was compliant with all required tailpipe pollutant emission limits under the WLTC cold and RDE legislative tests.

A number of non-regulatory tests were also conducted to understand if the emissions behaviour of the vehicle changed significantly outside of the legislative test, which might be an indication of prohibited emission strategies.

From the results of both legislative and non-legislative testing, DVSA does not have reason to believe that the Volvo V90 tested was non-compliant with its legal emissions performance requirements.

WLTC lab tests: Volvo V90

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM  (mg/km) PN (#/km)
Cold test 1 42.11 26.79 39.16 0.165 9.73E+09
Legislative limit 500 80 170 4.5 6.00E+11
Hot test 1 6.71 27.36 39.12 0.149 1.48E+09

RDE tests: Volvo V90

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM  (mg/km) PN (#/km)
COC figure (declared max RDE)   168     6.00E+11
Test 1 1.86 7.962     5.85E+07
Conformity factor limit   1.43     1.5
RDE legislative limit   114.4     9.00E+11

WLTC track tests: Volvo V90

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM  (mg/km) PN (#/km)
Test 1 40.9 32.2     2.27E+08

Go back to the list of diesel cars.

Results: petrol cars

Raw data for petrol car tests

You can download the unprocessed raw data showing the results of each test that was conducted on these vehicles.

Ford Fiesta

Vehicle details


Make: Ford

Model: Fiesta (2019MY)

Engine and fuel type: 998cc 92kW Petrol

Transmission: Manual 6 speed

Emission standard: Euro 6d-temp

Test reference: 33009

Tested: March 2021

Tests conducted

The following tests were completed on this vehicle to assess the emission control systems and tailpipe emissions:

  • vehicle preparation inspection
  • laboratory pre-conditioning
  • WLTC cold test in the laboratory
  • WLTC hot test in the laboratory
  • RDE on-road test
  • WLTC test carried out on a test track

Conclusion from tests

The Ford Fiesta was compliant with all required tailpipe pollutant emission limits under the WLTC cold and RDE legislative tests.

A number of non-regulatory tests were also conducted to understand if the emissions behaviour of the vehicle changed significantly outside of the legislative test, which might be an indication of prohibited emission strategies. From the results of both legislative and non-legislative testing, DVSA does not have reason to believe that the Ford Fiesta tested was non-compliant with its legal emissions performance requirements.

WLTC lab tests: Ford Fiesta

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
Cold test 1 187.6 17.23 13.42 16.39 0.82 2.52E+11
Legislative limit 1000 100 68 60 4.5 6.00E+11
Hot test 1 214.9 12.67 9.372 20.71 0.162 1.85E+11

RDE tests: Ford Fiesta

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
COC figure (declared max RDE)       126   9.00E+11
Test 1 23.3     13.96   1.29E+11
Conformity factor limit       2.1   1.5
RDE legislative limit       126   9.00E+11

WLTC track tests: Ford Fiesta

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
Test 1 159.4     16.83   1.48E+11
Test 2 178.7     12.75   1.18E+11

Go back to the list of petrol cars.

Ford Focus

Vehicle details


Make: Ford

Model: Focus (2020MY)

Engine and fuel type: 999cc 92kW Petrol

Transmission: Automatic

Emission standard: Euro 6d-temp

Test reference: 33010

Tested: April 2021

Tests conducted

The following tests were completed on this vehicle to assess the emission control systems and tailpipe emissions:

  • vehicle preparation inspection
  • laboratory pre-conditioning
  • WLTC cold test in the laboratory
  • WLTC hot test in the laboratory
  • RDE on-road test
  • WLTC test carried out on a test track

Conclusion from tests

The Ford Focus was compliant with all required tailpipe pollutant emission limits under the WLTC cold and RDE legislative tests.

A number of non-regulatory tests were also conducted to understand if the emissions behaviour of the vehicle changed significantly outside of the legislative test, which might be an indication of prohibited emission strategies. From the results of both legislative and non-legislative testing, DVSA does not have reason to believe that the Ford Focus tested was non-compliant with its legal emissions performance requirements.

WLTC lab tests: Ford Focus

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
Cold test 1 266.1 38.97 33.27 11.94 0.299 1.66E+11
Legislative limit 1000 100 68 60 4.5 6.00E+11
Hot test 1 162.9 8.848 5.711 4.037 0.116 3.42E+10

RDE tests: Ford Focus

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
COC figure (declared max RDE)            
Test 1 231.2     9.12   3.67E+10
Conformity factor limit       2.1   1.5
RDE legislative limit       126   9.00E+11

WLTC track tests: Ford Focus

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
Test 1 457.3     15.93   4.20E+10

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Kia Sportage

Vehicle details


Make: Kia

Model: Sportage (2020MY)

Engine and fuel type: 1591cc GDI Petrol

Transmission: Automatic

Emission standard: Euro 6d-temp

Test reference: 33018

Tested: April 2021

Tests conducted

The following tests were completed on this vehicle to assess the emission control systems and tailpipe emissions:

  • vehicle preparation inspection
  • laboratory pre-conditioning
  • WLTC cold test in the laboratory
  • WLTC hot test in the laboratory
  • RDE on-road test
  • WLTC test carried out on a test track

Conclusion from tests

The Kia Sportage was compliant with all required tailpipe pollutant emission limits under the WLTC cold and RDE legislative tests.

A number of non-regulatory tests were also conducted to understand if the emissions behaviour of the vehicle changed significantly outside of the legislative test, which might be an indication of prohibited emission strategies.

From the results of both legislative and non-legislative testing, DVSA does not have reason to believe that the Kia Sportage tested was non-compliant with its legal emissions performance requirements.

WLTC lab tests: Kia Sportage

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
Cold test 1 302.4 12.78 9.107 13.51 0.157 1.51E+11
Legislative limit 1000 100 68 60 4.5 6.00E+11
Hot test 1 207.7 8.353 5.928 15.45 0.169 9.23E+10

RDE tests: Kia Sportage

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
COC figure (declared max RDE) 374.22     96   6.00E+11
Test 1 191.1     9.2   1.62E+11
Conformity factor limit       2.1   1.5
RDE legislative limit       126   9.00E+11

WLTC track tests: Kia Sportage

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
Test 1 311.5     37.2   9.57E+10

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Mini Countryman

Vehicle details


Make: Mini

Model: Countryman Cooper S(2019MY)

Engine and fuel type: 1998cc 141kW Petrol

Transmission: Manual 6 speed

Emission standard: Euro 6d-temp

Test reference: 33149

Tested: March 2021

Tests conducted

The following tests were completed on this vehicle to assess the emission control systems and tailpipe emissions:

  • vehicle preparation inspection
  • laboratory pre-conditioning
  • WLTC cold test in the laboratory
  • WLTC hot test in the laboratory
  • RDE on-road test
  • WLTC test carried out on a test track

Conclusion from tests

The Mini Countryman was compliant with all required tailpipe pollutant emission limits under the WLTC cold and RDE legislative tests.

A number of non-regulatory tests were also conducted to understand if the emissions behaviour of the vehicle changed significantly outside of the legislative test, which might be an indication of prohibited emission strategies.

From the results of both legislative and non-legislative testing, DVSA does not have reason to believe that the Mini Countryman tested was non-compliant with its legal emissions performance requirements.

WLTC lab tests: Mini Countryman

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
Cold test 1 350.9 12.62 10.62 9.41 0.025 1.90E+10
Legislative limit 1000 100 68 60 4.5 6.00E+11
Hot test 1 326.5 7.963 6.41 7.434 0.017 8.01E+09

RDE tests: Mini Countryman

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
COC figure (declared max RDE)            
Test 1 651.6     24.77   5.19E+09
Conformity factor limit       2.1   1.5
RDE legislative limit       126   6.00E+11

WLTC track tests: Mini Countryman

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
Test 1 459.6     14.21   4.03E+09

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Mitsubishi Eclipse Cross

Vehicle details


Make: Mitsubishi

Model: Eclipse Cross (2019MY)

Engine and fuel type: 1499cc GDI Petrol

Transmission: Manual 6 speed

Emission standard: Euro 6d-temp

Test reference: 33023

Tested: May 2021

Tests conducted

The following tests were completed on this vehicle to assess the emission control systems and tailpipe emissions:

  • vehicle preparation inspection
  • laboratory pre-conditioning
  • WLTC cold test in the laboratory
  • WLTC hot test in the laboratory
  • RDE on-road test
  • WLTC test carried out on a test track

Conclusion from tests

The Mitsubishi Eclipse Cross was compliant with all required tailpipe pollutant emission limits under the WLTC cold and RDE legislative tests.

A number of non-regulatory tests were also conducted to understand if the emissions behaviour of the vehicle changed significantly outside of the legislative test, which might be an indication of prohibited emission strategies.

From the results of both legislative and non-legislative testing, DVSA does not have reason to believe that the Mitsubishi Eclipse Cross tested was non-compliant with its legal emissions performance requirements.

WLTC lab tests: Mitsubishi Eclipse Cross

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
Cold test 1 531.9 33.01 26.52 4.977 0.089 4.85E+10
Legislative limit 1000 100 68 60 4.5 6.00E+11
Hot test 1 373.3 16.68 12.66 6.282 0.013 2.41E+10

RDE tests: Mitsubishi Eclipse Cross

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
COC figure (declared max RDE)            
Test 1 255.5     2.97   2.78E+10
Conformity factor limit       2.1   1.5
RDE legislative limit       126   9.00E+11

WLTC track tests: Mitsubishi Eclipse Cross

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
Test 1 610.1     44.71   1.03E+11

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Nissan Qashqai

Vehicle details


Make: Nissan

Model: Qashqai (2020MY)

Engine and fuel type: 1332cc 117kW Petrol

Transmission: Automatic

Emission standard: Euro 6d-temp

Test reference: 3

Tested: March 2021

Tests conducted

The following tests were completed on this vehicle to assess the emission control systems and tailpipe emissions:

  • vehicle preparation inspection
  • laboratory pre-conditioning
  • WLTC cold test in the laboratory
  • WLTC hot test in the laboratory
  • RDE on-road test
  • WLTC test carried out on a test track

Conclusion from tests

The Nissan Qashqai was compliant with all required tailpipe pollutant emission limits under the WLTC cold and RDE legislative tests.

A number of non-regulatory tests were also conducted to understand if the emissions behaviour of the vehicle changed significantly outside of the legislative test, which might be an indication of prohibited emission strategies.

From the results of both legislative and non-legislative testing, DVSA does not have reason to believe that the Nissan Qashqai tested was non-compliant with its legal emissions performance requirements.

WLTC lab tests: Nissan Qashqai

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
Cold test 1 110.5 13.66 11.82 14.2 0.083 6.63E+10
Legislative limit 1000 100 68 60 4.5 6.00E+11
Hot test 1 26.73 1.596 0.815 12.63 0.048 3.19E+09

RDE tests: Nissan Qashqai

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
COC figure (declared max RDE)       90    
Test 1 77.3     16.38   7.20E+09
Conformity factor limit       2.1   1.5
RDE legislative limit       126   6.00E+11

WLTC track tests: Nissan Qashqai

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
Test 1 105.4     15.23   1.50E+10

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Renault Captur

Vehicle details


Make: Renault

Model: Captur (2020MY)

Engine and fuel type: 1332cc GDI Petrol

Transmission: Manual 6 speed

Emission standard: Euro 6d-temp

Test reference: 33266

Tested: April 2021

Tests conducted

The following tests were completed on this vehicle to assess the emission control systems and tailpipe emissions:

  • vehicle preparation inspection
  • laboratory pre-conditioning
  • WLTC cold test in the laboratory
  • WLTC hot test in the laboratory
  • RDE on-road test
  • WLTC test carried out on a test track

Conclusion from tests

The Renault Captur was compliant with all required tailpipe pollutant emission limits under the WLTC cold and RDE legislative tests.

A number of non-regulatory tests were also conducted to understand if the emissions behaviour of the vehicle changed significantly outside of the legislative test, which might be an indication of prohibited emission strategies.

From the results of both legislative and non-legislative testing, DVSA does not have reason to believe that the Renault Captur tested was non-compliant with its legal emissions performance requirements.

WLTC lab tests: Renault Captur

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
Cold test 1 80.03 13.67 11.79 8.572 0.094 5.27E+10
Legislative limit 1000 100 68 60 4.5 6.00E+11
Hot test 1 42.51 5.62 4.23 11.33 0.08 2.61E+09

RDE tests: Renault Captur

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
COC figure (declared max RDE)           6.00E+11
Test 1 26.06     29.7   1.42E+10
Conformity factor limit       2.1   1.5
RDE legislative limit       126   9.00E+11

WLTC track tests: Renault Captur

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
Test 1 95.9     13.5   1.40E+10

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Renault Clio

Vehicle details


Make: Renault

Model: Clio (2020MY)

Engine and fuel type: 999cc PFI Petrol

Transmission: Manual 5 speed

Emission standard: Euro 6d-temp

Test reference: 35224

Tested: February 2022

Tests conducted

The following tests were completed on this vehicle to assess the emission control systems and tailpipe emissions:

  • vehicle preparation inspection
  • laboratory pre-conditioning
  • WLTC cold test in the laboratory
  • WLTC hot test in the laboratory
  • RDE on-road test
  • WLTC test carried out on a test track

Conclusion from tests

The Renault Clio was compliant with all required tailpipe pollutant emission limits under the WLTC cold and RDE legislative tests.

A number of non-regulatory tests were also conducted to understand if the emissions behaviour of the vehicle changed significantly outside of the legislative test, which might be an indication of prohibited emission strategies.

From the results of both legislative and non-legislative testing, DVSA does not have reason to believe that the Renault Clio tested was non-compliant with its legal emissions performance requirements.

WLTC lab tests: Renault Clio

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
Cold test 1 326.9 33.91 30.41 16.57 1.632 8.56E+11
Legislative limit 1000 100 68 60 4.5 NA
Hot test 1 117.8 4.9 3.6 14.96 0.158 1.39E+11

RDE tests: Renault Clio

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
COC figure (declared max RDE)       60    
Test 1 249.9     11.64   5.41E+11
Conformity factor limit       2.1   1.5
RDE legislative limit       126   6.00E+11

WLTC track tests: Renault Clio

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
Test 1 318.9     24.0   1.06E+12
Test 2 389.0     8.7   6.17E+11

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Suzuki Vitara

Vehicle details


Make: Suzuki

Model: Vitara (2020MY)

Engine and fuel type: 1373cc 95kW Petrol

Transmission: Manual 6 speed

Emission standard: Euro 6d-ISC-FCM

Test reference: 34781

Tested: November 2021

Tests conducted

The following tests were completed on this vehicle to assess the emission control systems and tailpipe emissions:

  • vehicle preparation inspection
  • laboratory pre-conditioning
  • WLTC cold test in the laboratory
  • WLTC hot test in the laboratory
  • RDE on-road test
  • WLTC test carried out on a test track

Conclusion from tests

The Suzuki Vitara was compliant with all required tailpipe pollutant emission limits under the WLTC cold and RDE legislative tests.

A number of non-regulatory tests were also conducted to understand if the emissions behaviour of the vehicle changed significantly outside of the legislative test, which might be an indication of prohibited emission strategies.

From the results of both legislative and non-legislative testing, DVSA does not have reason to believe that the Suzuki Vitara tested was non-compliant with its legal emissions performance requirements.

WLTC lab tests: Suzuki Vitara

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
Cold test 1 191.0 21.75 18.48 9.95 0.136 2.36E+11
Legislative limit 1000 100 68 60 4.5 6.00E+11
Hot test 1 142.8 15.39 12.3 18.17 0.081 1.25E+11

RDE tests: Suzuki Vitara

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
COC figure (declared max RDE)       60   6.00E+11
Test 1 95.59     7.807   9.42E+10
Conformity factor limit       1.43   1.5
RDE legislative limit       85.8   9.00E+11

WLTC track tests: Suzuki Vitara

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
Test 1 168.5     6.718   1.16E+11

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Toyota Aygo

Vehicle details


Make: Toyota

Model: Aygo (2019MY)

Engine and fuel type: 998cc 53kW Petrol

Transmission: Manual 5 speed

Emission standard: Euro 6c

Test reference: 33195

Tested: February 2022

Tests conducted

The following tests were completed on this vehicle to assess the emission control systems and tailpipe emissions:

  • vehicle preparation inspection
  • laboratory pre-conditioning
  • WLTC cold test in the laboratory
  • WLTC hot test in the laboratory
  • RDE on-road test
  • WLTC test carried out on a test track

Conclusion from tests

The Toyota Aygo was compliant with all required tailpipe pollutant emission limits under the WLTC cold legislative test.

A number of non-regulatory tests were also conducted to understand if the emissions behaviour of the vehicle changed significantly outside of the legislative test, which might be an indication of prohibited emission strategies.

From the results of both legislative and non-legislative testing, DVSA does not have reason to believe that the Toyota Aygo tested was non-compliant with its legal emissions performance requirements.

WLTC lab tests: Toyota Aygo

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
Cold test 1 177.8 19.49 16.73 10.91 0.048 1.54E+11
Legislative limit 1000 100 68 60    
Hot test 1 66.27 10.6 8.563 13.89 0.041 4.35E+10

RDE tests: Toyota Aygo

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
Test 1 49.7     16.35   2.51E+11

WLTC track tests: Toyota Aygo

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
Test 1 91.95     8.62   1.05E+11

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Vauxhall Corsa

Vehicle details


Make: Vauxhall

Model: Corsa (2020MY)

Engine and fuel type: 1199cc 74kW Petrol

Transmission: Manual 6 speed

Emission standard: Euro 6d

Test reference: 33207

Tested: March 2020

Tests conducted

The following tests were completed on this vehicle to assess the emission control systems and tailpipe emissions:

  • vehicle preparation inspection
  • laboratory pre-conditioning
  • WLTC cold test in the laboratory
  • WLTC hot test in the laboratory
  • RDE on-road test
  • WLTC test carried out on a test track

Conclusion from tests

The Vauxhall Corsa was compliant with all required tailpipe pollutant emission limits under the WLTC cold and RDE legislative tests.

A number of non-regulatory tests were also conducted to understand if the emissions behaviour of the vehicle changed significantly outside of the legislative test, which might be an indication of prohibited emission strategies. From the results of both legislative and non-legislative testing, DVSA does not have reason to believe that the Vauxhall Corsa tested was non-compliant with its legal emissions performance requirements.

WLTC lab tests: Vauxhall Corsa

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
Cold test 1 373.2 25.64 22.2 9.197 2.933 1.84E+11
Legislative limit 1000 100 68 60 4.5 6.00E+11
Hot test 1 136.7 4.184 2.93 13.57 2.565 1.02E+11

RDE tests: Vauxhall Corsa

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
COC figure (declared max RDE)       60   6.00E+11
Test 1 231.5     6.487   2.19E+11
Conformity factor limit       1.43   1.5
RDE legislative limit       85.8   9.00E+11

WLTC track tests: Vauxhall Corsa

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
Test 1 488.1     6.109   2.40E+11

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Vauxhall Mokka

Vehicle details


Make: Vauxhall

Model: Mokka (2018MY)

Engine and fuel type: 1364cc Petrol

Transmission: Automatic

Emission standard: Euro 6d-temp

Test reference: 35923

Tested: July 2022

Tests conducted

The following tests were completed on this vehicle to assess the emission control systems and tailpipe emissions:

  • vehicle preparation inspection
  • laboratory pre-conditioning
  • WLTC cold test in the laboratory
  • WLTC hot test in the laboratory
  • RDE on-road test
  • WLTC test carried out on a test track

Conclusion from tests

The Vauxhall Mokka was compliant with all required tailpipe pollutant emission limits under the WLTC cold and RDE legislative tests.

A number of non-regulatory tests were also conducted to understand if the emissions behaviour of the vehicle changed significantly outside of the legislative test, which might be an indication of prohibited emission strategies. From the results of both legislative and non-legislative testing, DVSA does not have reason to believe that the Vauxhall Mokka tested was non-compliant with its legal emissions performance requirements.

WLTC lab tests: Vauxhall Mokka

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
Cold test 1 360.8 24.83 22.38 19.85 0.463 6.74E+11
Legislative limit 1000 100 68 60    
Hot test 1 160.1 6.776 5.764 24.81 0.158 3.25E+11

RDE tests: Vauxhall Mokka

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
COC figure (declared max RDE)       126    
Test 1 187.9     18.56   6.68E+11
Conformity factor limit       2.1    
RDE legislative limit       126    

WLTC track tests: Vauxhall Mokka

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
Test 1 398.4     24.86   6.77E+11

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Volkswagen Golf

Vehicle details


Make: Volkswagen

Model: Golf Life TSI (2020MY)

Engine and fuel type: 1498cc 96kW Petrol

Transmission: Manual 6 speed

Emission standard: Euro 6d-temp

Test reference: 33235

Tested: March 2020

Tests conducted

The following tests were completed on this vehicle to assess the emission control systems and tailpipe emissions:

  • vehicle preparation inspection
  • laboratory pre-conditioning
  • WLTC cold test in the laboratory
  • WLTC hot test in the laboratory
  • RDE on-road test
  • WLTC test carried out on a test track

Conclusion from tests

The Volkswagen Golf was compliant with all required tailpipe pollutant emission limits under the WLTC cold and RDE legislative tests.

A number of non-regulatory tests were also conducted to understand if the emissions behaviour of the vehicle changed significantly outside of the legislative test, which might be an indication of prohibited emission strategies.

From the results of both legislative and non-legislative testing, DVSA does not have reason to believe that the Volkswagen Golf tested was non-compliant with its legal emissions performance requirements.

WLTC lab tests: Volkswagen Golf

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
Cold test 1 65.58 18.56 15.99 21.89 0.116 5.74E+10
Legislative limit 1000 100 68 60 4.5 6.00E+11
Hot test 1 18.39 7.08 4.86 22.74 0.096 4.18E+10

RDE tests: Volkswagen Golf

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
COC figure (declared max RDE)            
Test 1 4.476     21.32   3.60E+10
Conformity factor limit       2.1   1.5
RDE legislative limit       126   6.00E+11

WLTC track tests: Volkswagen Golf

Test CO (mg/km) THC (mg/km) NMHC (mg/km) NOx (mg/km) PM (mg/km) PN (#/km)
Test 1 84.49     21.54   3.87E+10

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Results: light vans

Raw data for light van tests

You can download the unprocessed raw data showing the results of each test that was conducted on these vehicles.

Ford Transit

Vehicle details


Make: Ford

Model: Transit (2020MY)

Engine and fuel type: 1995cc Diesel

Transmission: Manual 6 speed

Emission standard: Euro 6d-temp

Test reference: 33206

Tested: May 2021

Tests conducted

The following tests were completed on this vehicle to assess the emission control systems and tailpipe emissions:

  • vehicle preparation inspection
  • laboratory pre-conditioning
  • WLTC cold test in the laboratory
  • WLTC hot test in the laboratory
  • RDE on-road test
  • WLTC test carried out on a test track

Conclusion from tests

The Ford Transit was compliant with all required tailpipe pollutant emission limits under the WLTC cold and RDE legislative tests.

A number of non-regulatory tests were also conducted to understand if the emissions behaviour of the vehicle changed significantly outside of the legislative test, which might be an indication of prohibited emission strategies.

From the results of both legislative and non-legislative testing, DVSA does not have reason to believe that the Ford Transit tested was non-compliant with its legal emissions performance requirements.

WLTC lab tests: Ford Transit

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM (mg/km) PN (#/km)
Cold test 1 53.32 39.5 47.09 0.073 2.44E+09
Legislative limit 740 125 215 4.5 6.00E+11
Hot test 1 3.644 53.04 57.82 0.056 1.29E+09

RDE tests: Ford Transit

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM (mg/km) PN (#/km)
COC figure (declared max RDE)   262.5     9.00E+11
Test 1 57.83 23.58     5.85E+08
Conformity factor limit   2.1     1.5
RDE legislative limit   262.5     9.00E+11

WLTC track tests: Ford Transit

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM (mg/km) PN (#/km)
Test 1 167.1 39.74     1.96E+09

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Renault Trafic

Vehicle details


Make: Renault

Model: Trafic (2018MY)

Engine and fuel type: 1598cc Diesel

Transmission: Manual 6 speed

Emission standard: Euro 6b

Test reference: 33248

Tested: April 2021

Tests conducted

The following tests were completed on this vehicle to assess the emission control systems and tailpipe emissions:

  • vehicle preparation inspection
  • laboratory pre-conditioning
  • NEDC cold test in the laboratory
  • NEDC hot test in the laboratory
  • RDE on-road test
  • WLTC test carried out on a test track

Conclusion from tests

The Renault Trafic was compliant with all required tailpipe pollutant emission limits under the NEDC cold legislative test.

A number of non-regulatory tests were also conducted to understand if the emissions behaviour of the vehicle changed significantly outside of the legislative test, which might be an indication of prohibited emission strategies.

From the results of both legislative and non-legislative testing, DVSA does not have reason to believe that the Renault Trafic tested was non-compliant with its legal emissions performance requirements.

NEDC lab tests: Renault Trafic

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM (mg/km) PN (#/km)
Cold test 1 243.8 100.9 138.5 0.228 1.08E+10
Legislative limit 740 125 215 4.5 6.00E+11
Hot test 1 54.6 142.9 165.6 0.251 8.03E+09

RDE tests: Renault Trafic

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM (mg/km) PN (#/km)
Test 1 457.3 262.4     6.57E+10

WLTC track tests: Renault Trafic

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM (mg/km) PN (#/km)
Test 1 83.2 325.3     5.34E+10

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Toyota Hilux

Vehicle details


Make: Toyota

Model: Hilux (2019MY)

Engine and fuel type: 2393cc 110kW Diesel

Transmission: Automatic

Emission standard: Euro 6b

Test reference: 33913

Tested: May 2021

Tests conducted

The following tests were completed on this vehicle to assess the emission control systems and tailpipe emissions:

  • vehicle preparation inspection
  • laboratory pre-conditioning
  • NEDC cold test in the laboratory
  • NEDC hot test in the laboratory
  • RDE on-road test
  • WLTC test carried out on a test track

Conclusion from tests

The Toyota Hilux was compliant with all required tailpipe pollutant emission limits under the NEDC cold legislative test.

A number of non-regulatory tests were also conducted to understand if the emissions behaviour of the vehicle changed significantly outside of the legislative test, which might be an indication of prohibited emission strategies.

From the results of both legislative and non-legislative testing, DVSA does not have reason to believe that the Toyota Hilux tested was non-compliant with its legal emissions performance requirements.

NEDC lab tests: Toyota Hilux

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM (mg/km) PN (#/km)
Cold test 1 50.49 94.36 99.5 0.333 6.38E+09
Legislative limit 740 125 215   6.00E+11
Hot test 1 18.73 71.15 75.24 0.102 1.49E+09

RDE tests: Toyota Hilux

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM (mg/km) PN (#/km)
Test 1 70.4 136     7.45E+08
Test 2 35.78 594.9     2.06E+08
Test 3 4.72 449.3     7.95E+08

WLTC track tests: Toyota Hilux

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM (mg/km) PN (#/km)
Test 1 14.55 150.1     1.44E+10
Test 2 2.55 274.4     1.23E+09

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Toyota Proace

Vehicle details


Make: Toyota

Model: Proace (2020MY)

Engine and fuel type: 1997cc 90kW Diesel

Transmission: Manual 6 speed

Emission standard: Euro 6d

Test reference: 33030

Tested: May 2021

Tests conducted

The following tests were completed on this vehicle to assess the emission control systems and tailpipe emissions:

  • vehicle preparation inspection
  • laboratory pre-conditioning
  • WLTC cold test in the laboratory
  • WLTC hot test in the laboratory
  • RDE on-road test
  • WLTC test carried out on a test track

Conclusion from tests

The Toyota Proace was compliant with all required tailpipe pollutant emission limits under the WLTC cold and RDE legislative tests.

A number of non-regulatory tests were also conducted to understand if the emissions behaviour of the vehicle changed significantly outside of the legislative test, which might be an indication of prohibited emission strategies.

From the results of both legislative and non-legislative testing, DVSA does not have reason to believe that the Toyota Proace tested was non-compliant with its legal emissions performance requirements.

WLTC lab tests: Toyota Proace

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM (mg/km) PN (#/km)
Cold test 1 29.32 31.86 33.96 0.17 8.40E+09
Legislative limit 500 80 170 4.5 6.00E+11
Hot test 1 2.932 27.95 29 0.173 7.31E+09

RDE tests: Toyota Proace

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM (mg/km) PN (#/km)
COC figure (declared max RDE)   105     6.00E+11
Test 1 5.72 9.93     9.19E+09
Conformity factor limit   1.43     1.5
RDE legislative limit   150.15     9.00E+11

WLTC track tests: Toyota Proace

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM (mg/km) PN (#/km)
Test 1 173.4 17.86     6.01E+09

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Volkswagen Caddy

Vehicle details


Make: Volkswagen

Model: Caddy (2020MY)

Engine and fuel type: 1968cc 75kW Diesel

Transmission: Manual 5 speed

Emission standard: Euro 6d-temp

Test reference: 33275

Tested: May 2021

Tests conducted

The following tests were completed on this vehicle to assess the emission control systems and tailpipe emissions:

  • vehicle preparation inspection
  • laboratory pre-conditioning
  • WLTC cold test in the laboratory
  • WLTC hot test in the laboratory
  • RDE on-road test
  • WLTC test carried out on a test track

Conclusion from tests

The Volkswagen Caddy was compliant with all required tailpipe pollutant emission limits under the WLTC cold and RDE legislative tests.

A number of non-regulatory tests were also conducted to understand if the emissions behaviour of the vehicle changed significantly outside of the legislative test, which might be an indication of prohibited emission strategies.

From the results of both legislative and non-legislative testing, DVSA does not have reason to believe that the Volkswagen Caddy tested was non-compliant with its legal emissions performance requirements.

WLTC lab tests: Volkswagen Caddy

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM (mg/km) PN (#/km)
Cold test 1 21.78 36.32 47.27 0.192 4.41E+08
Legislative limit 500 105 170 4.5 6.00E+11
Hot test 1 4.303 34.98 42.46 0.102 2.36E+08

RDE tests: Volkswagen Caddy

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM (mg/km) PN (#/km)
COC figure (declared max RDE)   220     6.00E+11
Test 1 7.749 46.35     5.96E+08
Conformity factor limit   2.1     1.5
RDE legislative limit   220.5     9.00E+11

WLTC track tests: Volkswagen Caddy

Test CO (mg/km) NOx (mg/km) HC+NOx (mg/km) PM (mg/km) PN (#/km)
Test 1 63.46 62.5     1.35E+09

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Results: HGVs

In this section:

Raw data for HGV tests

You can download the unprocessed raw data showing the results of each test that was conducted on these vehicles.

MAN TGX 26.500

Vehicle details


Make: MAN

Model: TGX 26.500 N3 Artic (2017MY)

Engine and fuel type: 12419cc, 368kW Diesel

Transmission: Automated manual

Emission standard: Euro 6 Step C

Test reference: 33449

Tested: August 2021

Tests conducted

The following tests were completed on this vehicle to assess the emission control systems and tailpipe emissions:

  • vehicle preparation inspection
  • on-road conformity test

Conclusion from tests

The MAN TGX was compliant with all required tailpipe pollutant emission limits under the on-road conformity legislative test. When DVSA tested the vehicle to the EU ISC protocol as part of the on road conformity test, DVSA found compliance for THC, CO and NOx emissions. All monitored emissions fell well below the test limits.

Additionally DVSA tested this vehicle with a 90% pay load (test 2).

From the results, DVSA does not have reason to believe that the MAN TGX tested was non-compliant with its legal emissions performance requirements.

On-road conformity test: MAN TGX 26.500

Conformity factor result using CO2 window calculation method:

Test Carbon monoxide (CO) Total hydrocarbons (THC) Nitrogen oxides (NO and NO2)
Legislative Limit 1.5 1.5 1.5
Test 1 0.07 0.07 0.16
Test 2 0.04 0.02 0.03

Conformity factor result using work window calculation method:

Test Carbon monoxide (CO) Total hydrocarbons (THC) Nitrogen oxides (NO and NO2)
Legislative Limit 1.5 1.5 1.5
Test 1 0.08 0.08 0.17
Test 2 0.05 0.02 0.37

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Renault DT46

Vehicle details


Make: Renault

Model: T46 (2014MY)

Engine and fuel type: 10837cc Diesel

Transmission: Automatic

Emission standard: Euro 6 Step B

Test reference: 33451

Tested: March 2021

Tests conducted

The following tests were completed on this vehicle to assess the emission control systems and tailpipe emissions:

  • vehicle preparation inspection
  • on-road conformity test

Conclusion from tests

The Renault T46 was initially not compliant with all required tailpipe pollutant emission limits under the on-road conformity legislative test.

On road conformity tests resulted in nitrogen oxides (NOx) emissions above legislative limits, which warranted further discussion with the manufacturer. The initial test results are shown as test 1, test 2 and test 3.

On initial contact with Renault Trucks following the first tests, they inspected the vehicle for any vehicle faults that could be causing the high emission output. Renault also provided confirmation that this vehicle was subject to a recall campaign relating to exhaust aftertreatment degradation on this product and others with similar engines.

Renault had already notified the relevant approval authorities about the recall campaign with an associated plan to check and remedy affected vehicles. The recall itself involves replacement of the selective catalytic reduction (SCR) catalyst due to deactivation of the active material caused by low temperature water degradation. This is a failure mode linked to the specific catalyst coating in this application, which is changed in recalls and later applications. The issue affects Euro VI Step B and C vehicles. The vehicle tested is covered by Euro VI Step B standards.

The we tested did not have the SCR catalyst replaced as part of the recall campaign at the time of DVSA first testing. After diagnostic investigation ruled out other potential faults that may contribute to high emission levels, Renault’s analysis of the test data confirmed that SCR conversion efficiency appeared low. Therefore, after-treatment degradation was identified as the most likely root cause of the high NOx emissions. Renault were given the opportunity to inspect the vehicle and rule out any other potential issues before replacing the aftertreatment system.

During Renault’s inspections, witnessed by DVSA, no other emissions control system issues were found on the vehicle. Therefore, the root cause of NOx emissions being exceeded was confirmed as SCR degradation. A plan for replacing the SCR system was agreed with DVSA, followed by repeat testing to check for emissions control improvements.

A repeat emission test was conducted (test 6) which showed NOx exceedance. This was attributed to the fact that whilst the new SCR was fitted, the required self-adaptions in the electronic control unit (ECU) had not been performed. However, once the adaptions had been set, the vehicle was shown to be compliant, shown in the results as test 7.

From the results, and associated recall campaign, DVSA does not have reason to believe that the Renault T46 tested was non-compliant with its legal emissions performance requirements.

On-road conformity test: Renault DT46

Conformity factor result using CO2 window calculation method:

Test Carbon monoxide (CO) Total hydrocarbons (THC) Nitrogen oxides (NO and NO2)
Legislative Limit 1.5 1.5 1.5
Test 1 0.14 0.03 1.47
Test 2 0.17 0.02 1.09
Test 3 0.17 0 2.54
Test 4 0.14 0.04 5.3
Test 5 0.09 0.03 2.28
Test 6 0.2 0.03 6.87
Test 7 0.28 0.03 0.53

Conformity factor result using work window calculation method:

Test Carbon monoxide (CO) Total hydrocarbons (THC) Nitrogen oxides (NO and NO2)
Legislative Limit 1.5 1.5 1.5
Test 1 0.15 0.03 1.51
Test 2 0.19 0.03 1.21
Test 3 0.19 0 2.37
Test 4 0.17 0.05 5.81
Test 5 0.11 0.03 2.59
Test 6 0.2 0.04 7.72
Test 7 0.34 0.03 0.47

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Annex: Emissions reduction technologies

This annex explains some of the emissions reduction technologies mentioned in the report.

Exhaust gas recirculation (EGR)

Exhaust gas recirculation (EGR) displaces intake air with a defined amount of inert exhaust gas. The presence of inert exhaust gas in the combustion chamber reduces both peak combustion temperatures and the amount of oxygen available. This in turn reduces formation of nitrogen oxides (NOx), but can also cause an increase in the emissions of particulate matter (soot).

EGR has been used for many years on both light-duty and heavy-duty engines. Use of EGR may lead to compromises on other vehicle characteristics, such as:

  • particulate emissions
  • driveability
  • fuel economy
  • transient performance
  • diesel particulate filter (DPF) regeneration interval

However, a well-designed and calibrated EGR system should minimise any negative impacts.

There are a number of types of EGR system available to manufacturers including:

  • internal
  • external

Cooled internal exhaust gas regulation (EGR)

This occurs within the combustion chamber or exhaust manifold interface, and is set by the timing of the closing of the exhaust valve.

Following the completion of the exhaust stroke, the exhaust valve remains open during the start on the induction stroke, causing some of the exhaust in the exhaust manifold to be drawn back into the combustion chamber. As there is no additional control over this, the amount of EGR that occurs is generally kept low.

External exhaust gas regulation (EGR)

Some of the exhaust gas is directed through a pipe from the exhaust system back into the inlet manifold.

The EGR flow is regulated by an EGR valve, and is set according to a range of engine operating conditions and parameters which are controlled by the electronic control unit (ECU) software and calibration.

High pressure EGR systems take exhaust gas from before the turbocharger. For some Euro 6 vehicles, low pressure EGR systems have been introduced, which takes exhaust gas from after the diesel particulate filter and introduces it into the intake system. Often high pressure and low pressure EGR are used in combination.

Cooled exhaust gas regulation (EGR)

This is the same as external EGR, but the recirculated exhaust gases pass through a cooler before re-entering the engine. This allows EGR to be applied over a wider range of engine operating conditions, and can provide a further reduction in the combustion temperature.

Diesel oxidation catalyst (DOC)

A diesel oxidation catalyst (DOC) promotes the oxidation of several of the exhaust components. These are oxidised using oxygen that is present in the diesel exhaust, in the presence of a catalyst. The components include:

  • carbon monoxide, which forms carbon dioxide
  • hydrocarbon (HC), which oxidises to become carbon dioxide and water
  • soluble organic fraction of particulate matter (SOF)

In addition to targeting regulated pollutants, a DOC can also control several non-regulated HC species, such as aldehydes and polycyclic aromatic hydrocarbons (PAHs), as well as reducing the odour of the exhaust.

DOCs can also oxidise nitric oxide (NO) exiting the engine into nitrogen dioxide (NO2). If a DOC is used on its own, this increase in the more harmful nitrogen dioxide can have a negative impact on air quality. However, generation of NO2 may prove to be a benefit when used prior to a diesel particulate filter (DPF) or selective catalytic reduction (SCR), by helping regeneration in a DPF and enhancing the emissions conversion performance of a SCR.

Diesel particulate filter (DPF)

A diesel particulate filter is a device to trap the particulate matter from the exhaust gas of a diesel engine.

They generally consist of some form of filter material which traps the particles as the exhaust flows through it. During use, soot accumulates in the filter, increasing the back pressure in the exhaust. To allow continued efficient operation, accumulated soot needs to be regularly removed. This can be achieved on the vehicle by a process known as regeneration.

There are a number of ways to achieve this, including:

  • increasing the exhaust temperature through engine management (late fuel injection or injection during the exhaust stroke) - diesel particulate burns at about 600 °C, so this temperature needs to be maintained for the regeneration period (for example, a period of higher engine load may need to be sustained)
  • adding a fuel borne catalyst, which reduces the combustion temperature of the particulate from 600 °C down to 350 to 450 °C - this requires a small additional tank to hold additive, plus the associated plumbing, but this is more fuel efficient as no additional diesel fuel is required
  • passive regeneration – the presence of NO2, generated in the diesel oxidation catalyst (DOC), can also reduce the combustion temperature allowing the DPF to regenerate continuously, avoiding the fuel consumption penalties associated with raising the exhaust temperature to initiate regeneration

The alternative to on-board regeneration is to remove the DPF from the vehicle, though this is often impractical and is not a common solution.

Lean NOx trap (LNT)

Unlike a petrol engine, a diesel engine’s combustion process and exhaust gas is ‘lean’, which means it has excess oxygen present. As a result, a standard diesel oxidation catalyst cannot convert NOx (nitric oxide and nitrogen dioxide) emissions.

A lean NOx trap is a device which looks similar to a standard diesel oxidation catalyst that acts as a molecular sponge, chemically trapping NOx emissions (by adsorption) rather than converting them. They are a type of NOx Storage Catalyst (NSC).

The amount of NOx a trap can hold is dependent on its temperature as well as other constituents such as sulfur. The optimum temperature window is typically around 250 to 450°C. However, once the trap is full, it cannot adsorb any more NOx. The trap must therefore be periodically ‘purged’ by briefly creating ‘rich’ conditions (excess fuel) in the exhaust.

When this happens, the trap releases and simultaneously converts the NOx to nitrogen and water vapour, a process often termed “deNOx”. The frequency with which this happens will depend on the system and the driving conditions, but can be several times an hour.

Selective catalytic reduction (SCR)

Selective catalytic reduction (SCR) is an alternative catalyst system that is able to convert NOx (nitric oxide and nitrogen dioxide) even under ‘lean’ exhaust gas conditions.

The reaction takes place with ammonia (typically supplied as AdBlue) in the presence of a catalyst, which is either oxides of base metals (such as copper, iron, vanadium, molybdenum and tungsten), zeolites, or various precious metals.

To be efficient, the SCR must be at its nominal operating temperature (typically 250 to 450°C) and it can reduce NOx emissions by up to 95%. Critically, unlike the other systems described here, SCR relies on a consumable reagent (that provides the ammonia) and only reduces emissions whilst the catalyst is being supplied or “dosed” with this reagent. Urea has the trade name of AdBlue, and is also known as Diesel Exhaust Fluid (DEF).

As a result, regulations require:

  • a visible and audible driver warning when reagent levels are low
  • that vehicle performance is restricted or engine restart is prevented if the driver fails to refill the system

The temperature of the SCR is determined primarily by the exhaust gas. Therefore, the placement of the SCR in relation to the engine and the engine’s duty cycle are critical with respect to the SCR’s performance. The SCR canister is relatively large. In addition to the SCR, the following are also required:

  • urea/diesel exhaust fluid (DEF) tank - the urea dosing rate will vary by engine and vehicle, but this tank will be sized to avoid vehicle owners having to refill too frequently - the tank also contains heaters and sensors
  • a dosing pump to pump the urea from the tank into the exhaust pipe just before the SCR
  • a control module to control the amount of urea added
  • pre and post SCR NOx sensors to ensure that the SCR system is operating correctly

Although readily available, the main design constraint is the amount of space needed for the installation.

Ammonia catalyst

SCR requires ammonia, which is derived from the urea. The ideal ratio of ammonia to NOx is 1:1.

Under certain conditions, such as low efficiency, extreme low temperature, extreme high temperature, and high mass flow, not all of the ammonia might be used in the NOx reduction process, and some of it may exit the SCR. This is known as ammonia slip.

To prevent the release of ammonia at the tailpipe, an additional catalyst is placed immediately after the SCR. There are various terms for these devices, including:

  • ammonia oxidation catalyst (AOC)
  • ammonia slip catalyst (ASC)
  • clean up catalyst (CUC)

Any ammonia can either be oxidised to NOx, which is not really desirable, or it can be selectively oxidised to produce water and nitrogen. The ammonia catalyst is often packaged in the same can as the SCR.

Combination devices

Almost all diesel engines these days are turbocharged. The resulting emissions will be dealt with using a combination of techniques. This commonly includes:

  • exhaust gas recirculation, diesel oxidation catalyst, and diesel particulate filter
  • exhaust gas recirculation, diesel oxidation catalyst, lean NOx trap, and diesel particulate filter
  • exhaust gas recirculation, diesel oxidation catalyst, selective catalytic reduction, and diesel particulate filter
  • exhaust gas recirculation, diesel oxidation catalyst, lean NOx trap, diesel particulate filter and selective catalytic reduction
  • exhaust gas recirculation, diesel oxidation catalyst, lean NOx trap, diesel particulate filter, selective catalytic reduction and ammonia slip catalyst

Gasoline particulate filter (GPF)

Gasoline particulate filters (GPF) have been introduced to reduce particle number emissions from gasoline direct injection (GDI) vehicles. The filters use wall-flow substrates that were first developed for diesel particulate filters.

The GPF regenerates passively, but an active regeneration assist is needed to prevent filter plugging during low temperature duty cycles.

Port fuel injection (PFI)

Port fuel injection (PFI) injects fuel into the intake ports just upstream of each cylinder’s intake valve.

The main advantage of PFI when compared to direct injection is the extra time allowed for fuel and air mixing, delivering a more homogenous air and fuel mixture.

Aftertreatment hydrocarbon injector (AHI)

Aftertreatment or auxiliary hydrocarbon injector (AHI) is a fuel injector located in the exhaust upstream of the diesel oxidation catalyst (DOC) and diesel particulate filter (DPF) and is used to assist with raising the DPF exhaust gas inlet temperature when an active DPF regeneration is required.

These systems are typically employed in heavy duty diesel engines.

Three-way catalyst (TWC)

Three-way catalytic converters are effective in preventing air pollution from rich-burn and stoichiometric engines fuelled by natural gas, propane and gasoline. Three-way catalysts are designed to perform multiple oxidation reactions and reduction reactions simultaneously to convert air pollutants that are present in the exhaust to harmless gases.

Exhaust gas composition depends on the air to fuel ratio (AFR) at which the engine operates. Rich mixtures (lambda less than 1) produce high concentrations of nitrous oxides (NOx), carbon monoxide (CO) and hydrocarbons (HCs). The exhaust gases of lean fuel mixtures (lambda greater than 1) contain reduced amounts of NOx and HCs.

The three-way reactions take place over specially formulated precious metal catalysts that allow the reduction of NOx by CO and the oxidation of CO and HC by oxygen to occur simultaneously. The catalyst functions most efficiently when the engine oscillates around the stoichiometric point (lambda equal to 1).

Three-way catalysts are typically used with an air to fuel ratio (A/F) controller to maintain a tight control of air fuel ratio (AFR) around stoichiometry. These controllers use a feedback signal from an oxygen sensor located in front of the catalyst and are required for the three-way catalyst to operate properly.

Carbon dioxide (CO2) reducing technologies

For carbon dioxide (CO2) measurements, there are multiple factors which can contribute to a vehicle’s performance when testing in a laboratory.

These include vehicle-based CO2 reducing technologies such as:

  • stop-start system
  • electrification or hybridisation
  • intelligent battery system management
  • gear shift scheduling

Other things that can have an impact are:

  • ambient temperature
  • road load simulation
  • driver dynamicity

NEDC approved vehicles

For vehicles that were approved under NEDC test procedures, CO2 values obtained under type approval test conditions can be challenging to reproduce.

This can be as a result of ensuring any CO2 reducing technologies deployed are operating in their entirety and as designed. As well as replicating to the full extent the boundary conditions under which the vehicle was type approved.

There are many ways manufacturers can follow regulations to optimise CO2 performance under type approval test conditions. Without having the full scope of test set-up and vehicle preparation information, this adds an additional factor of complexity in a third-party test environment.

WLTP approved vehicles

The introduction of the WLTP regulation reduced these possibilities, and we observe this in our emissions test programme, where typically CO2 values declared at type approval can be reproduced relatively easily in the same third-party environment.

Conformity factor

An emissions conformity factor is a ratio of the respective Type 1 laboratory limit value.

For example: for the Euro 6d emission standard, the M1 category WLTC NOx limit for diesel is 80mg/km. The RDE NOx limit is expressed as conformity factor equal to 1.43, so this will be 1.43 multiplied by 80mg/km, giving a limit value of 114.4mg/km.

This is then applied as the respective NOx limit value for RDE testing.